Work consists of 69 pages, 14 data tables, 26 illustrations, 4 attachments, 31 literature sources is used

The purpose of this work is to investigate informational reliability of the “man-machine-environment” system and find out the difficulties of audible information spread in noisy environment and also estimate the quality of this information.

„Man-machine-environment“system informational reliability is being analyzed in literature review section. An extensive attention intended for audible information quality in noise, influence of using hearing protectors also discussed. Finally spatial hearing and sound localization biological aspects reviewed, qualitative indexes of audible signal analyzed.

Research analysis showed that significant account for audible information propagation has its amplitude frequentative characteristic but man can dissociate even these audible signals, of which speech interference level (SIL) is poor, or less than 5 dBA. Also determined that informational signals are informative when their level is at least 5 dBA higher in one of four octave bands and when hearing protector suppression is less than 20 dBA. Results can be used as extra information for professional risk assessment.

Raktažodžiai: audible information, information quality, systems „man-machine environment” reliability, noise.